Treatment of raw protein

ABSTRACT

THE INVENTION CONCERNS A PROCESS FOR TREATING A RAW PROTEIN SOURCE, FOR EXAMPLE FISH, TO OBTAIN A DRY PROTEIN CONCENTRATE OF HIGH BIOLOGICAL VALUE. THE PROTEIN CONCENTRATE IS GROUND UP, SOAKED IN A WEAK FORMALDEHYDE IN WATER SOLUTION, THEN DRIED. THE PRODUCT IS A CONCENTRATE WHICH LACKS THE OFFESIVE ODOUR OF MANY FISH MEALS. FURTHER IT IS FIT FOR HUMAN CONSUMPTION AND CAN BE STORED FOR LONG PERIODS IN A PACKET ON A SHELF, I.E. WITHOUT FREEZING.

United States Patent 3,707,381 TREATMENT OF RAW PROTEIN Kenneth Henry Sharp, 3 Cedar, Southdale Road, Southdale, Johannesburg, Republic of South Africa No Drawing. Filed Mar. 12, 1970, Ser. No. 19,111 Claims priority, application Republic of South Africa, Apr. 29, 1969, 69/2,915 Int. Cl. A23j 1/04 U.S. Cl. 99-18 8 Claims ABSTRACT OF THE DISCLOSURE The invention concerns a process for treating a raw protein source, for example fish, to obtain a dry protein Concentrate of high biological value. The protein concentrate is ground up, soaked in a weak formaldehyde in water solution, then dried. The product is a concentrate which lacks the offensive odour of many fish meals. Further it is fit for human consumption and can be stored for long periods in a packet on a shelf, i.e. without freezing.

This invention relates to an improved process for treating raw protein which results in a stable protein concentrate which can be stored indefinitely at ambient temperatures in tropical and subtropical climates.

At present, for example, the fishing industry off the Southern and South West African coast is hampered by the fact that the fish caught do not stay fresh for any length of time, Also, known processes for producing a protein concentrate from fresh wet fish such as solvent extraction or azeotropic distillation tend to be expensive.

An object of the present invention is to provide a process which the applicant believes has certain advantages over existing processes. For instance the applicants process allows for storage of fish for long periods at sea thus enabling fishing vessels to stay at sea until their holds are full. Further the applicants process yields as end product a protein concentrate which can be stored at room temperatures as indicated above. Of importance is the fact that the protein concentrate is fit for human consumption. The process is particularly useful in the fishing industry but is also suitable for the treatment of protein from any other source, for example whale meat, plankton, livestock, game and others.

According to the invention a process for the preparation of a stable protein concentrate from a raw fresh protein source includes the steps of comminuting the raw material, soaking the material in a solution of formaldehyde in water with the formaldehyde added to the water to a concentration of between 0.01% to 1%, removing at least some and preferably most excess solution to yield a slurry, and thereafter treating the slurry to remove the remaining excess moisture.

The preferred treatment of the slurry to remove the remaining excess moisture is to freeze the material in the slurry to a solid state, thaw the frozen material and then remove the resultant excess moisture by mechanical means, for example pressure filtration or a screw press.

The invention is also directed to a process for the treatment of raw fresh protein to allow storage of the protein without freezing, which includes the steps of comminuting the raw material, soaking the material in a solution of formaldehyde in water with the formaldehyde added to the water to a concentration of between 0.01% and 1%, and removing at least some but preferably most of the excess solution to yield a slurry, which is then stored.

According to this aspect of the invention when it is applied to the fishing industry, the first three steps of the 3,707,381 Patented Dec. 26-, 1972 process may be carried out on board a vessel at sea. This part of the process results in a sterilised slurry which may be stored in the holds of the vessel for extended periods. Also the vessel when fully loaded will store a greater tonnage of protein since some water in the body of the fish will have been removed already. When the vessel returns to harbour the slurry may be pumped to a plant on or near the wharf where the remainder of the process is carried out.

In the specification the word comminute shall include any operation whereby the raw material is broken down to small particles for example grinding, cutting up, mincing, mashing and others.

In order to illustrate the invention a practical embodiment is described below.

The process according to the invention is particularly useful in the fishing industry. For example off the Southern and South-West African coast at present the mean average catch of some types of fish is approximately 40% of the total hold capacity taken over the whole fishing season. By using the process according to the invention it would be possible to approach 100% because the vessels could stay out at sea long enough to fill the holds, without fear of the catch going bad.

The process is as follows:

Freshly caught fish are treated whole or may be deheaded and degutted and washed with fresh Water, if required. The fish are passed through a grinder or mincing machine. The fish are all thoroughly ground up and the ground mass is placed in a tank containing 0.1 to 0.5% formaldehyde in water solution at a natural pH. The weight of the solution used should be approximately the same weight as the ground mass of fish. Depending on how finely the fish have been ground the ground mass of fish should be allowed to soak in the solution for one to ten minutes. The more finely the mass of fish is ground, the more efiiciently will the solution contact the protein in the ground mass. If the particles are larger it is necessary to allow them to soak for a longer period. Agitation of the ground mass of fish will assist this part of the process.

The formaldehyde solution apart from its action on the protein, acts to sterilise the tank and the ground fish.

The next step is to remove excess solution by decantation or pressure or vacuum filtration or by other conventional means. After removing the excess solution there remains a fish slurry which is sterile and can be stored for lengthy periods in the hold of a trawler or factory ship or on whatever vessel is used for this part of the process. It will be understood that the steps of the process thus far can be carried out conveniently at sea.

The next stage of the process is preferably performed on the shore but could be carried out at sea in a factory ship having the necessary equipment. The slurry is pumped to a plant on or near the wharf. The slurry is then frozen solid at a temperature between 5 and 20 C. This step is important for the process. -It is important that all parts of the material in the slurry freeze solid and it is necessary to leave the slurry in this frozen condition for a period between one half an hour and five hours in length. The time period also depends on the coarseness of the grind. For coarser grinds longer periods are required so that the whole mass is frozen solid right through and not just on the outside. It is to be noted that freezing to a slush is not enough.

screw press, pressure filtration, dewatering screens or by other means.

At this stage fats and oils and odoriferous materials may be removed by emulsifying with standard known 4 meat or horse meat or game the higher concentration is preferable.

The various samples of protein concentrate prepared according to the process of this invention has been subemulsifiers and removing the emulsified oils and fats and 5 jected to tests which are set out below in the following odoriferous materials. Alternatively the fats and oils and examples. odoriferous materials may be removed by using solvent EXAMPLE 1 extraction methods with known solvents for fats and oils A sample of d h ded d de utted pilchard as caught for example P PY alcohol: ethyl alcohol dlchloro' off the coast of South-West Africa was treated as follows: ethylene, hexane and Others The sample was thoroughly ground and a 100 parts by F nally, if necessary, the product is dr1ed 1n air by conweight of the ground sample was mixed with 20 parts Vehtlonal meal'ls to f final Percentage molsture Stumble of 0.2% formaldehyde solution. The mixture was stirred for Storagedrylng Should be done at temperatures for fifteen minutes. Excess solution was removed by o bel W a ut 0 C- t aVOld denaturing the pf squeezing to 50 lbs. per square inch in a pressure filter Other conventional means may be used either with or and the resultant pulp was f o n to minus 10 C for without the a d of reduced P eexample P 3 four hours. The solid frozen mass was thawed to room 'y g methods or Solvent extractlon PmeeSses y be temperature in warm water and the pulp again squeezed used. to 50 lbs. per square inch until all excess solution had been Alternatlvely, the Protelh y h drled of its moisture removed. This material was then treated with isopropyl fi t ndthen have the fats and oils removed. alcohol in a refluxing apparatus for three hours and air If desired, the dried protein can be ground further to a d i d at 50 Q Thi i ld d a d i d d d i d fi fine powder. Th s results n a dry powdery pr t l C9 tein concentrate which was submitted for a nitrogen centrate which is very suitable for human consumption b l triaL (The usual white [at test) and can be stored in a container for example a polythene T fi h protein concentrate was tested together i h bag at emblem temperaturesa standard reference protein of dried defatted whole egg The product has not been heated to excess. Heating d a Series of d i d b Causes a collapse of the Proielh fibres Into hard Tables I, II and III show the results of these tests. P These The Product 15 of a lower dellslty than that The sample of fish protein concentrate was remarkably produced by presently known means. Fur h r th 0 free from any fishy flavour and it was impossible to detect is markedly whiter than fish meal and fish protein conany deterioration in the organoleptic properties of a centrates produced by known processes. sample kept in a polythene bag at room temperature for In an alternative form of the invention the first stages about five weeks. of the process are as described above namely, grinding Also, the grittiness usually found in samples of fish the material, soaking it in a formaldehyde solution, and flours produced by other processes was not a characterremoving excess solution by some mechanical means, but istic of the sample.

TABLE I.PROTEIN VALUES Proiteir con n P (N X 635) v ercent of percent Digest- Biological (moisture ability of value of Material free) protein protein N .P.U.2 N.P.V.3

Fish protein concentrate- 92.36 97. 65:0. 283 88.2 1.944 Beans 27. 0'1 85.15:]:0. 709 60. 8i1. 564 i iii? Eggs s4. 91 9143:0546 96.1=l;1.186 93.7 79.6

I Percent utilization of absorbed (digestible) fraction of rotein 'n d 1 Percent util zable protein in protein components of pi oduct. 1 pm net 8 Weight of utihzable protein in 100 parts (by weight) of product on a moisture-free basis.

then instead of freezing and the subsequent steps the slurry is subjected to spray drying thereby removing the remaining excess moisture from the protein.

In one modification the material may be subjected to all the steps described above namely, grinding, mixing with formaldehyde solution, pressing out excess solution, freezing, thawing, again pressing out excess solution and then finally subjecting the material to spray drying. In addition the material may be treated either before or after the final drying stages for the removal of fats and oils and odoriferous materials.

In another modification the material may be steam cooked after it has been thawed.

In yet another modification of the process, instead of freezing and the subsequent steps, the material may be subjected to solvent extraction to remove water from the protein.

With regard to the concentration of the formaldehyde solution the following is to be noted. Depending on the nature of the fresh protein source, the concentration of the formaldehyde solution should be varied. For example for the more tender meats such as chicken, a lower concentration of formaldehyde in water is preferable. So for chicken meat a 0.1% solution of formaldehyde in water is used. If a 0.5% solution is used the protein may tend to be degraded during the subsequent drying process. On the other hand for a tougher meat such as Whale TABLE II.GROWTH OF RATS OVER 17 DAYS AND B WATER WEIGHTS AT END OF TRIAL ODY Mean body-water Mean weight weight gain of after 17 rigsiver days of ays experiment Material (grams) (grams) Fish protein concentrate 23.1 49. 3 Beans 7. 5 38. 1 Eggs 25. 1 61. 2

TABLE III.-DATA 0N UREA N AND NON-UREA N U PUT 0F RATS DURING BALANCE PERIOD 0 T 1 These figures indicatethe extent to which the absorbed protein is wasted through excretion in the urine as urea. The figures are inversely correlated with the biological value of the protein. i

6 EXAMPLE 2. TESTS TABLE I-Continued Weight of product- The treatment procedure is given in Table I. T t

as Percent of The analysis report given in Table H. Treatment (grams) original 5 7 Fine minced mackerel agitate in ultra- 250 100 TABLE I.TREATMENT PROCEDURE sonic tvibrator with hexane (1:1) 10 [Tests 1-5 were done using deheaded and degutted ilchard. Tests 7 9 as and 10 were done using maclrerefi g gzfggk gggg Agltate in ultrasonic vibrator l0 Weight of product- 10 P i 1 ti Test Percent of fess so u on 118 47 No prior freezing No. Treatment (grams) 0 3 165101113 at C. 1 Coarse minced pilchard 440 100 aw press 73 32 900 (2.0. of 0.2% formalin 2 hours stir 15 minutes Press out solution Pressure filter-51 hours s? 2 Weight wet fish 435 5 Air Y 0 34 14 pH f solution 7.l (strong emulsion in hexane) D fig. fi ggfi l f f 9- Fine minced mackerel 365 100 Thaw and press out solution 185 43 Henna to fish (2:1) for 3 days Stand in hexane 48 hours 185 43 Press out hexane 320 Press out hexane 650 c.c. 0.2% formalin 2 days Air dry hexane at 40 C. to 80 18 Press out solution 245 7 20 No freezing 2 (a) Fine minced pilchard 250 100 Press to 2,000 -l q- 174 37 250 c.c. 0.2% formalin Y to 3 20 Temperature 8 0. (strong fish smell) Stir 20 in t s I.P.A. twice at 1:1 I2PBess OltiyQllflfiOl'l u 210 84 -W 62 16 1 0.0. orma n Stir 1s mini'nes 10 Fine minced mackerel 250 100 Press out solution 170 68 500 formalin i Freeze 16 hours at -15 C. Stir 1 hour Thaw and press out solution 95 37 Press out solution 200 0.0. 0.2% formalin Instant freeze in solid pH 1.5 OOz/hexane super- Stir 15 minutes cooled l iquld Press out solution 108 43 Freeze 16 hours at 15 C.- Thaw 16 hours Thaw and press out solution 100 40 Press Out Solution Stand in hexane, 16 hours Wash on with hexane Press out hexane y to 50 25 Air dry to 41 16 2 (b) Fine minced pilchard 250 100 Soda bicarbonate to pH 8.2 500 0.0. 0.2% formalin Stir 15 minutes Temperature 15 0. Press out solution. 230 Freeze 16 hours at --15 C.- Thaw and press out solution 150 60 TABLE IL-ANALYSIS REPORT FOR ABOVE TESTS 300 0.0. 0.2% formalin Temperature 35 0. Percent of Hexane, 95% Protein, tir 20 minutes fats alcohol tats fat and Press t ti 176 70 Test Protein and oils and oils water free 200 01. g.2% formalin No. (as is) Moisture Ash percent percent percent p Stir 2 hours 81. 7 9. 0 5. 7 0. 70 5. 0 95 Press out solution 100 68. 3 8.3 4.1 0. 90 14 8 89 Freeze 16 hours at 15 C. 68. 0 9. 1 4. 6 3. 7 20. 1 96 Thaw and press out solution 91 71. 6 9. 5 4. 8 1. 0 l2. 5 92 dry to 39 84. 2 9. 2 5. 9 0.30 4. 3 1 97 81. 8 9. 2 5. 1 O. 70 4. 9 95 3 Fine minced pilchald 250 69. 1 8. 0 5. 0 13. 6 17. 5 93 600 0.0. 0.5% formalin 79. 4 9. 6 6. 3 2. 7 6. 0 94 pH 84. e 4. a 7.1 0.89 7.2 1 95 Stir 15 minutes 80. 2 9. 4 6. 8 3. 6 8. 9 1 99 Press out solution 195 Freeze 16 hours at 15 C. 1 Results are suspect but show that the process has not adversely Thaw and press out solution 130 52 affected the protein. 200 cc. 0.2% formalin H 1.5 Stir 2 hours gress oili; slolutiort 15 C 110 44 reeze ours a Thaw and press out solution 102 41 What IS clalmed Hexane (1 1? twice and 1. A process for the preparation of a stable proteln 3 ,23 3 exam 48 19 concentrate from a raw fish protein source, which consists essentially of 4 Fine minced pilchard 250 100 (A) comml'nuting said raw material,

l ir i 'i 'l iz n e s 0 (B) soaking said raw material in a solution of formal- Free ole samp e 16 o s 5 C- dehyde in water to provide a slurry of the protein d l 100 40 33 1: ifgjgggj; 2; material, sald formaldehyde being present 1n the sofiir ig eme 2% lution in an amount ranging from 0.01 to 1.0% by I.P.A. 1:1 2 hours weight, Filter and air dry to 37 15 (C) removing at least some and preferably most of the a Fine minced pilchard 700 100 free water of the slurry,

g ggzg g (D) freezing the raw material 1n the slurry to a solid ress o t S l ti n 1 a state to permit the formaldehyde to release water Freeze 16 hours at 5 C. Thaw and press out solution 308 44 from protem Air dry to 189 27 (E) thawing the frozen materlal, and Split into 5(a) and 50)). (F) treating the thawed material to remove any re- 5 (a) Wash in hexane 3 times 100 100 malning free water including said water released from dry 76 21 said protein. 5 (b)..-. As is for analysis 39 27 2. The process of claim 1, wherein free water is removed from the system through spray drying.

3. The process of claim 1, wherein free water is removed from the system through solvent extraction.

4. The process of claim 1, wherein the final step of removing the remaining free water is achieved through spray drying.

5. The process of claim 1, wherein the final step of removing the free water is achieved through cooking the material.

6. The process of claim 1, which includes the step of removing fats and oils and odoriferous materials through solvent extraction.

7. The process of claim 1, which includes the step of removing fats and oils and odoriferous materials through emulsification.

for the solvent extraction is isopropyl alcohol.

8 References Cited Rose: The Condensed Chemical Dictionary, 1969, p. 429. v

Brody: Fishery By-Products Technology, 1965, pp.

RAYMOND N. JONES, Primary Examiner R. B. ANDEWELT, Assistant Examiner US. Cl. X.R. 

